Rotary steam engine

ABSTRACT

In a rotary steam engine, a novel form of piston and rotary element permitting continuous circular movement of the piston, a new steam admission valve, and an exhaust port through the outer wall of the rotating element, a new type of cylinder wall construction for additional strength and safety.

United States Patent 1 1 Nardi 1 1 ROTARY STEAM ENGINE [75] Inventor: Anthony Nardi, Burlington, Mass.

[73] Assignee: Clean Energy, Inc., Newton Highlands, Mass.

22 Filed: Aug. 30, 1973 21 App]. 190.; 392,948

[52] US. Cl. 418/161, 418/225 [51] Int. Cl. F0lc 1/00 [58] Field of Search 418/160, 161, 164, 165, 418/225, 227, 183, 184

[56] References Cited UNITED STATES PATENTS 137,065 3/1873 Fisher 418/165 144,941 11/1873 Woods 597,793 1/1898 Tay1or.. 949,605 2/1910 Taylor 1,214,981 2/1917 Wikander [451 Feb. 11, 1975 Primary Examiner-C. J. Husar Assistant Examiner-Leonard Smith Attorney, Agent, or Firm-C. Yardley Chittick [57] ABSTRACT In a rotary steam engine, a novel form of piston and rotary element permitting continuous circular movement of the piston, a new steam admission valve, and an exhaust port through the outer wall of the rotating element, a new type of cylinder wall construction for additional strength and safety.

6 Claims, 12 Drawing Figures PATENTED E81 1 I975 SHEET 3 OF 3 1 ROTARY STEAM ENGINE BACKGROUND OF THE INVENTION Rotary steam engines of the type herein disclosed are old in the art. Early constructions may be found in patents to Fisher, No. 137,065, Taylor, No. 597,793, Taylor, No. 949,605 and Conklin 1,270,498.

In this type of steam engine there is no reciprocating piston. Instead each piston is permanently attached to the rotating cylinder walls and moves continuously in one direction. The inner transverse edge of each piston engages and slides along the cylindrical surface of a stationary inner body. The inner body carries a plurality of rotatable elements (ordinarily one more than the number of pistons) mounted for rotation in a succes sion of cavities in the inner body.

The rotatable elements act to form the ends of the curved cylinders. The construction permits the piston on reaching the end of its stroke, to pass the rotatable element to move into the next cylinder.

The radially outermost part of each rotatable element forming the end of the cylinder is in steam tight sliding engagement with the rotating walls of the cylin der.

In order that the piston may pass the rotatable element, it is essential that the piston and the rotatable element be in a form which might be said to be roughly in the nature of paired gear teeth. Thus the piston would represent an internal tooth designed to cooperate with external teeth on the rotatable element. In

some of the early forms disclosed in the prior art, it was considered desirable to gear the rotating part of the engine to the rotatable element in such manner that when the piston reached the rotatable element, the latter would be positively rotated by the gearing so that the piston would enter a complementary cavity in the rotatable element and thus to pass thereby. In other forms in the prior art, the piston came into positive engagement with one of the stationary blades of the rotatable element and forced the blade to rotate, thereby permitting passage of the piston into the next curved cylinder.

In all of the prior constructions, the shape of the piston and the shape of the blades of the rotatable elements did not provide for efficient passage of the piston past the rotatable element. There was a leakage of steam, excessive condensation, undue wear of the engaging portions, inefficiency in the location of the exhaust ports, inefficiency in the performance of the steam admission ports and inability to change the time of steam cut-off.

SUMMARY OF THE INVENTION In the present invention, the piston, which is attached to the outer walls of the engine with its inner edge slidable along the cylindrical surface of the inner fixed body, is generally in the form of a large gear tooth with its inner end in the form of a smaller gear tooth of different configuration. The rotatable element which permits the passage of the piston has four blades generally in the shape of large gear teeth. At the root of adjacent blades, the opposed surfaces are shaped in the form of two small adjacent teeth designed to cooperate closely with the small tooth on the inner end of the piston. The major portion of each wall blade has substantially the reverse configuration of the walls of the piston. Thus, as the piston comes close to the face of the blade which is then acting as the end of the curved cylinder and with the exhaust port closed, the pressure generated between the piston and the blade is usually sufficient to induce starting rotation of the blade. Immediately after the start of rotation, the tooth formation on the inner end of the piston will have reached its position of engagement in the previously referred to tooth formations that are at the roots of the adjacent blade surfaces. Thus the blade is started in its rotation by the rising pressure between the piston and the blade surface and is compelled to continue its rotation by the engagement of the small toothed end of the piston with the corresponding tooth formation between adjacent blades. If the pressure between the piston and blade is insufficient to start rotation, the piston will engage the blade at its outer end to compel rotation. The shape of the engaging surfaces is such that they roll against each other until the small inner teeth take over.

There are, in the preferred form of the invention, two pistons spaced 180 apart and three rotatable elements (each with four blades) spaced 120 apart. Thus there is always at least one steam cylinder in operation and there will never be any position of dead center. As a result, the rotation of the outer part of the engine is continuous and the driving force provided by the steam is substantially uniform. The rotating outer part of the engine acts as a fly wheel and maximum torque is always available from 0 rpm to top speed.

Another feature of the present invention is the location of the steam ports at the root positions between each adjacent pair of blades in each rotatable element. By so locating the steam entrance ports, steam is admitted because the face of the blade which now constitutes the pressure end of the curved cylinder and the rear pressure face of the piston which has just passed between two blades of the rotatable element. The admission of steam occurs automatically and precisely at the right moment for maximum efficiency.

The shape of the steam admission ports is also important. These ports are long and narrow and, as a result, when they open, they open much in the nature of a poppet valve in that a maximum steam admission area is provided almost instantly. Likewise, when cut-off occurs, the steam is cut off sharply.

These and other desirable features of the invention will become more apparent as the description proceeds with the aid of the accompanying drawings in which:

FIG. 1 is an isometric perspective view of the engine with parts broken away to show the cylinder walls, the pistons and rotatable elements, the steam supply system and the elongated steam admission ports.

FIG. 2 is a side elevation of the engine to reduced scale showing the exterior generally.

FIG. 3 is a side elevation of FIG. 2 viewed from the left with the left hand mounting removed. The side plates are cut away to show the interior parts more clearly.

FIG. 4 is a fragmentary side elevation showing the fixed location of the exhaust port in relation to the piston. This view also shows the steam valve actuating means.

FIGS. 5, 6, 7, 8, 9, 10, 11 and 12 show in enlarged detail, the configuration of the pistons and rotatable blades and a succession of positions assumed by the piston and blades as the piston reaches the end of its stroke and induces rotation of the blocking blade to establish the start of the next power stroke.

DESCRIPTION OF A PREFERRED EMBODIMENT The Stationary Parts of the Engine The general organization of the engine will be understood by reference to FIGS. 1, 2 and 3. There is a strong horizontal mounting shaft 2 which supports the engine. This shaft is hollow and has therein a steam supply pipe 4. Shaft 2 is splined at 6 whereby it may be keyed against rotation when positioned in its mounts 8 and 10 (see FIG. 2).

Shaft 2 has mounted thereon two sets of bearings 12 and 14 indicated in FIG. 2. These bearings are adequate to carry the load of the rotating engine. Bearing 12 is shown in detail in FIGS. 1 and 3. Each bearing comprises an inner tapered race 16, an outer tapered race 18 and rollers 20 therebetween.

Two spaced circular face plates 22 and 24 are mounted on shaft 2 (see FIG. 1). Between plates 22 and 24 is a cylindrical main body or steam chest 28 keyed to shaft 2 to prevent rotation. The face plates 22 and 24 are secured to body 28 by the ends of three steam pipes 100, 102 and 104 which extend transversely of the steam chest. The construction and'operation of these pipes will be explained in more detail hereinafter. The steam chest or body 28 is hollow and has an outer configuration comprising three semicylindrical cut-away areas or gaps spaced 120 apart. The outer discontinuous cylindrical surface of the hollow steam chest or body 28 forms the inner surface of the curved cylinder or expansion chamber. The interior of this surface is reached by the steam to maintain therein a high temperataure and thus to increase the thermal efficiency. The cut-away areas or gaps are indicated in FIGS. 1 and 3, at 30, 31 and 32. In each of the three areas is located a four bladed rotatable element. Two of the elements are visible in FIG. 1 at 34 and 36 and the third one at 35 in FIG. 3.

Element 34 is mounted for rotation on a hollow shaft 38 which extends from plate 22 to plate 24 and element 36 is mounted for rotation on a hollow shaft 40 which likewise extends from plate 22 to plate 24.

The third rotatable element 35 not visible in FIG. 1 but shown in FIG. 3 is spaced 120 from elements 34 and 36 and is identically positioned and mounted on a hollow shaft 39 in its semi-circular transverse cut 31 in body 28 similar to cuts and 32.

Each of the elements 34, and 36 has four identical blades marked A, B, C and D for element 34, E, F, G and H for element 36 and l, J, K and L for element 35. These blades at their transverse ends fit closely between plates 22 and 24. All of the outer radial ends of all of the blades are grooved as at 42 to receive steam seals 44. The friction between seals 44 and the semicircular faces 30, 31 and 32 that they engage is moderate so that the elements 34, 35 and 36 may be rotated easily.

The curvature of the transverse surfaces of each of the blades corresponds exactly to the curvature of the outer cylindrical surface of main body 28. That is to say, for example, the surface b of blade B of element 34 and the surface h of blade H of element 36 constitute extensions of the cylindrical surface section 46 of body 28. Thus in element 34 when the blade face b is aligned with surface 46 of body 28, the blade face d of blade D will likewisebe'aligned with the adjacent body surface 48. Similarly, in element 36 when blade face h is aligned with surface 46, blade face f will be aligned with surface 50.

The object of the construction just described is to permit the moving piston, which will soon be defined in detail, to slide smoothly from the body surface to the blade surface at the end of its stroke and from the blade surface to the body surface at the beginning of the stroke. The aligned blade and body surfaces constitute the stationary inner wall of the steam cylinder.

All of the structure disclosed thus far is stationary in space, being mounted on the stationary non-rotating shaft 2. (The elements 34, 35 and 36 are, of course, rotatable on their own axes 38, 39 and 40 but the axes are fixed in plates 22 aand 24.)

The Rotating Parts of the Engine The outer bearing races 18 carry side plates 52 and 54. The structure of side plate 52 includes an annular portion 56 about which are driving gear teeth 58. Adjacent teeth 58 is another annular portion 60 of greater diameter. The interior periphery 62 (see FIG. 1) of portion 60 closely surrounds plate 22 and a steam seal 64 is provided between these adjacent narrow cylindrical surfaces. The outer flange 66 of side plate 52 is adjacent a cylindrical member 68 having side flanges 70 and 72. Bolts 74 connect flanges 66 and 70 in steam tight relation. The inner cylindrical surface of member 68 comprises the outer wall of the steam cylinder.

Similarly, on the other side of the engine, side plate 54 is mounted on its bearing 14 on shaft 2. Side plate 54 may include gear teeth 76 as shown in FIGS. 1 and 2. The outer annular portion 78 shown in FIG. 1 has its inner periphery as at 80 overlying the exterior 82 of face plate 24 in the same manner that interior periphery 62 of portion 60 overlies the edge of plate 22. The outer flange 84 of side plate 54 abuts flange 72 and these flanges are bolted together in steam tight relation.

In the construction just described, the side plates 52 and 54 and the cylindrical member 68 to which they are bolted are rotatable around shaft 2 and the stationary interior body 28 which includes the related three rotatable elements 34, 35 and 36.

The rotating parts of the engine also revolve within a fixed volute condenser 85 plainly shown in FIGS. 1, 2, 3 and 4. This condenser and moving exhaust ports running from the cylinders to the condenser will be described hereinafter.

The Curved Cylinders The interior annular surface 86 of side plate 52 and the interior annular surface 88 of the outer portion 78 of side plate 54 provide facing walls which close the annular space between the interior of cylindrical member 68 and the exterior cylindrical surface of main body 28 and the aligned blade surfaces of elements 34, 35 and 36.

This structure provides the basic succession of curved cylinders of which there are three. The first cylinder (see FIG. 3) extends from face a of blade A of element 34 to face e of blade E of element 36. The second cylinder Y extends from the face 2' of blade E of element 36 to the face i of blade I of element 35. The third cylinder Z extends from face i of blade I of element 35 to the face a of blade A of element 34.

For convenience the curved spaces just defined will be called cylinders even though they are rectangular in cross section.

There are two pistons 90 and 92 which are attached to the interior of cylindrical member 68 and walls 86 and 88 and located 180 apart. Each piston has a stroke equal to the distance between the blades that define the ends of the cylinders. Thus, assuming that the rotating parts of the engine are turning clockwise as viewed in FIGS. 1 and 3, the piston 90 is close to the end of its stroke in cylinder Z since face a of blade A defines the end of the cylinder Z in which piston 90 is then located. Similarly, piston 92 is not quite half way through its stroke in the bottom cylinder Y whose ends are defined by face e of blade E and face iof blade I. Cylinder X in FIG. 3 has no piston therein.

The Pistons and Rotatable Elements As has been previously mentioned, there are two pis-' tons 90 and 92 and three cylinders X, Y and Z. Each piston is securely bolted to the outer cylinder wall 68 and the annular side walls 86 and 88 in steam tight relation. In cross-section, the piston is symmetrical and its inner edge is grooved as at 112 to hold therein a steam seal which rests against and slides along the stationary surfaces which comprise the inner walls of the cylinders. Such inner wall of cylinder X in FIG. 1 consists of face I) of blade B, surface 46 of body 28 and face 11 of blade H.

A major problem in the design of rotary engines has been in the shape of the piston and the blades of the ro tatable elements. Heretofore the constructions which required the rotation of the blocking elements by gearing or by actual engagement of the piston with the blocking element have not been successful. The construction about to be described permits the piston and cylinder to be of large cross-section resulting in a more powerful engine and the blocking blades may be put into rotation by the build up of pressure between the piston and the blade surface at the end of the stroke. If, due to leaky seals, insufficient pressure is built up to start rotation of the blocking blades, the piston will make actual engagement with the blade to compel rotation in a quiet efficient manner as the piston passes from one cylinder to the next. The inner end of the piston is in sealing engagement with root surfaces of adjacent blades so that the steam which is automatically admitted at the very beginning of the next stroke will have maximum effectiveness.

In FIG. 5 the relationship of piston 90 to blade A is substantially the same as that shown in FIG. 1. The curvature of surfaces d and a of blades D and A is the same as the cylindrical surfaces 46, 48 and 50 of body 28. For convenience in reference, the radius of this cylindrical surface is called R.

The surface 114 of piston 90 is also part of a cylinder whose radius may be the same as R but preferably is R plus about one-fourth inch. The surface 114 is so disposed on piston 90 that when it has advanded to the position of FIG. 6, the outer edges of faces a and 114 will be the first parts to engage as at 115. Thereafter as the piston continues its advance through the positions of FIGS. 7 and 8, the blade A will have started its rotation and there will be rolling engagement between surfaces 114 and 0' along a line moving inwardly of the two faces.

The inner end of piston 90 as at 116 is in the form of a gear tooth designed to cooperate with the female gear tooth formation present at 118 at the root of the blades A.and D. Thus by the time the piston 90 has reached the position shown in FIG. 8 with the faces a and 114 about to end their contact, gear tooth 116 acting with the tooth surfaces 118 takes over and continues the rotation of the blades A and D. As previously explained, the rotatable element comprised of blades A, B, C and D is mounted on a hollow bearing shaft 38. The friction forces present between blades A, B, C and D, the bearing 38, the face plates 22 and 24 and the semicylindrical cutaway area 30 are low and easily overcome to start rotation of the blades.

While rotation may be started. as previously explained by the actual engagement of the outer edge of surface 114 with the outer edge of surface m1 at 115 as shown in FIG. 6, the preferred method of starting rotation is by the creation of adequate fluid pressure between the piston face I14 and blade face a.

As shown in FIGS. 3 and 4, there are two fixed exhaust ports 120 and 122 that pass through the cylindrical wall 68 and through a cylindrical cover plate 124 to discharge all exhaust gases and condensate into the fixed volute condenser within which the moving parts of the engine rotate. Each exhaust port is about l5 in advance of its respective piston. In FIG. 4, piston is still about 30 from the end of its stroke and as the piston continues its approach toward the surface a of blocking blade A defining the end of cylinder Z, fluid continues to pass through exhaust port 120 into the condenser 85.

When exhaust port 120 has completely passed the edge of face a of blade A, the remaining space then between face 114 of piston 90 and face a is sealed. As piston 90 moves on toward face a there is a rapid build up in pressure, so much so that as soon as blade D is released from the restraining force of piston tooth 116 resting thereon, which release occurs when tooth I16 reaches the end of surface (I, rotation of the blades commences in a smooth noiseless manner. This is followed immediately by engagement of tooth 116 with the female tooth formation 118 to continue the rotation of the blades from the position of FIG. 7 through the positions shown in FIGS. 8, 9, 10 and 11.

The teeth 116 and 118 are so designed that there will be contact between the lower forward corner of tooth 116 and the adjacent surface on the forward side of tooth 118 as shown in FIGS. 10 and 11. When the parts have reached the position of FIG. 11, steam admission is beginning, forcing piston 90 to commence its stroke in the next cylinder X. Blade A is forced to its final position as shown in FIG. 12 in which its face a is now in alignment with surface 46 of body 28 so that the piston can travel unimpeded thereover as it is driven by the steam now entering cylinder X through ports 113 and located in the root space between blades A and D.

Piston 90 then continues its stroke through cylinder X until blocking blade E is approached. Exhaust port 120 passes the tip of blade E sealing the space between piston 90 and face e of blade E. The same procedure is then repeated as piston 90 passes blade E to enter the next cylinder Y.

In the meanwhile, piston 92 is continuing its power stroke through cylinder Y as piston 90 passes blocking blade A. When piston 92 passes its next blocking blade I, piston 90 will be on its power stroke in cylinder X. Thus there is always a power stroke in operation to drive the other piston past its blocking blade into the start of its next power stroke in the next cylinder.

The Steam Supply Means and Valving Mechanism It will be understood in the disclosure in FIGS. 1 and 3 that the pistons and related structures are rotating clockwise. To maintain this movement, steam must be admitted at the appropriate time in each successive cylinder to act against the face of the blade that then forms the pressure end of the cylinder and the rear face of the piston.

The steam reaches each of the three cylinders through the following structure. The steam supply pipe 4 extends through shaft 2 to the interior of the steam chest body 28. Three radial steam passages 94, 96 and 98 (see FIG. 3) lead away from pipe 4 to connect with transverse pipes 100, 102 and 104 the ends of which extend out of both sides of body 28 and through face plates 22 and 24 in attaching relation. Pipes 100, 102

' and 104 lead in turn to a first set of pipes 106, 108 and 110 running across the exterior face of face plate 22 and to a second set of pipes (not shown) running across the exterior face of face plate 24. These two sets of pipes connect with the opposite ends of hollow shafts 38, 39 and 40 which carry rotatable elements 34, 35 and 36, respectively. By supplying steam to both ends of hollow shafts 38, 39 and 40, a more uniform temperature throughout the system can be maintained.

Steam valving mechanism is located within shafts 38,

39 and 40 and is so arranged that steam can pass through the elongated admission ports which are located at the juncture of each pair of adjacent blades of each of the elements 34, 35 and 36. Two such ports are shown at 113 and 115 in FIG. 1 and FIGS. 5 to 12.

Each of shafts 38, 39 and 40 is attached to plates 22 and 24 and fixed against rotation. Each shaft has one or more elongated ports 126 directed at an angle of 45 toward the starting pressure end of each cylinder. Ports 126 in shaft 38 are shown in FIGS. 9, 10, 11 and 12.

Within each shaft 38, 39 and 40 is a tubular steam valve. One such valve 128 is shown in FIGS. 5 to 12. Valve 128 has one or more elongated ports 130. This valve is rotatable within its shaft 38 so that the fixed ports 126 and movable ports I30 can be brought into alignment. This construction can be seen in FIGS. 9, 10, l l and 12. In FIG. 9, the ports are out of alignment. In FIGS. and 11, the ports are moving toward alignment. In FIG. 12, the ports 126 and 130 are fully in alignment.

Thus when the three sets of ports, 1) those at the root of adjacent blades such as ports 113 and 115 shown in FIG. 1 which rotate with the blades, 2) the fixed ports 126 through the shafts that carry the rotatable blades,

and 3) the movable ports 130 in the rotatable valve 128' are brought into first partial and then full alignment as shown in FIGS. 11 and 12, steam can flow into the related cylinder behind the piston. Steam admission preferably begins when the piston 90 has traveled 7 beyond top dead center as in FIG. 11.

Ports 113 and 126 become fully aligned as soon as the piston 90 has caused 90 rotation of the blocking blade. that is, by moving blade A from the position in FIG. 5 through 90 to its final position in FIG. 12. These ports 113 and 126 remain in alignment until the arrival of the next piston causes another 90 rotation of the blades and a new alignment of the next set of ports 113, 115 between blades D and C in the root area with ports 126.

It will be appreciated that after the piston has left the blade surface a to pass along the cylindrical surface 46, for example, of the main body 28, there is no tendency for the rotor blades to shift position because the face areas engaged by the steam are exactly equal. The balanced forces thus hold the blades against rotation until the arrival of the next piston.

The admission of steam to the cylinder is controlled by the rotation of steam valve 128 to bring its port 130 into alignment with the already aligned ports 113 and 126. In FIG. 9 the steam valve 128 is closed. In FIGS. 10 and 11, it is shown being rotated toward open position. In FIG. 12, it is fully open, with port 130 aligned with shaft port 126 and rotor port 113.

At any selected point in the stroke of the piston, valve 128 can be rotated to the left to cut off the steam so that expansion of the steam already in the cylinder can continue thereby to increase operating efficiency.

The mechanism for causing automatic operation of valve 128 will now be explained. Referring now to FIG. 4 which is a fragmentary view generally similar to the upper part of FIG. 3 but looking from the opposite side of the engine, the tubular valve 128 extends beyond the end of rotor shaft 38 and beyond the outside face of face plate 24. A cam 132 is fixed to the end of valve 128. One cam lobe 134 cooperates with a spring 136 so that the valve is held against rotation in its normally closed condition such as shown in FIG. 9.

Attached to the exterior of rotating side plate 54 (not shown in FIG. 4) is a striker plate 138 which is circularly aligned with a second lobe 140 on cam 132.

Striker plate 138 is angularly related to piston 90 so that when the piston has caused blade A to rotate 90 to bring ports 113 and 126 into alignment as in FIG. 12, the striker plate will have engaged lobe 140 to rotate cam 132 counter-clockwise as viewed in FIG. 4 through 45 (overcoming spring 136) to likewise bring steam port 130 into alignment with the other two aligned ports 113 anad 126 as in FIG. 12.

This aligned condition of the ports continues for an extent controlled by the circumferential length of striker plate 138. When the rear end of striker plate 138 passes beyond lobe 140, the tubular steam valve 128 is released and spring 136 instantly returns the valve to closed position. Steam admission and cut-off accordingly occur automatically and precisely as desired.

It should be mentioned that all three sets of ports, those in the rotor between the blades, those in the fixed rotor shaft and those in the rotatable steam valve are long and narrow, similar to ports 113 and shown in FIG. 1. This is very desirable as a small angular rotation of the steam valve 128 causes the port openings to go from fully closed to fully open, giving sharp admission and cut-off in the same manner as a poppet valve.

The stationary volute condenser 85 is in steam tight but sliding engagement with cover plate 124 and the clamping bands 141 and 142 that hold plate 124 in position on the flanges 70 and 62. Suitable labyrinth seals are indicated at 144 which permit rotation of the engine at normal speeds without undue wear. The steam or condensaate first discharged into the condenser 85 through exhaust ports and 122 will ordinarily be delivered to a secondary condenser and the water therefrom will be fed back to the boiler.

Since this engine may be operated at high steam pressures, the construction must be such as to insure complete structural safety. lt will be noted that the outer side plates 52 and 54 are of adequate thickness and are bolted by many bolts to the heavy flanges 70 and 72 of the outer wall 68. The only path for possible steam leakage is between the inner faces 86 and 88 of side plates 52 and 54 and body 28, thence past the seals 64 and 81 in the outer peripheries of face plates 22 and 24 and finally past the seals 146 that engage the inner rotating faces of the outer bearing races 18. Thus the steam pressure is safely confined with the engine.

From the foregoing, it will be understood that the rotary steam engine disclosed herein is of simple construction, strong and relatively light in relation to its potential power output. lt has only one continuously rotating moving part which is carried by two adequate bearings on a fixed shaft. It has three intermittently operating four bladed rotatable elements and three automatically operated oscillating steam valves. No lubrication is required except in the main bearings and on the rotor shafts.

An operative engine about 2 feet in diameter, not including condenser, with cylinders being about l2 square inches in cross-section and having a piston stroke of about 16 inches, will develop about 150 HP at 300 RPM with a mean effective pressure of 400 psi at 450F. At 600 RPM, the engine will develop about 300 HP at the same working pressure.

Because of the rotation of the outer cylindrical cylinder wall, any condensate developed behind the piston will tend to collect on this outer wall and will be squeegeed from it as the outer wall passes over the newly established blocking blade, thus to be discharged more readily through the oncoming exhaust port which is just in advance of the next piston. Similarly, any condensate on the stationary inner wall of the curved cylinder is squeegeed thereform by the next advancing piston to flow out the exhaust port.

The annular space between outer cylinder 68 and the cover plate 124 is a sealed area which acts as insulation to maintain the working temperature of wall 68 thereby to increase the efficiency.

The above disclosure will suggest to others skilled in the art modifications which are within the scope of the invention as defined by the appended claims.

I claim:

1. In a rotary steam engine having a stationary discontinuous cylindrical inner wall and rotating outer and side walls to form a curved cylinder, a piston attached to the rotating walls and a four bladed rotatable element associated with the inner wall, one of said blades extending across and blocking said cylinder, means for causing rotation of said rotatable element through 90 whereby said piston may pass thereby, said means comprising curved faces on the blades of said rotatable elements of the same radius as said inner walls, curved faces on said piston having a radius greater than the radius of said inner wall, the inner end of said piston comprising a gear tooth, cooperating gear tooth faces at the root areas between adjacent blades of said rotating element, and an exhaust port through said outer wall located in advance of its related piston a distance such that when said exhaust port has moved beyond said blocking blade, said piston will have started its travel over the curved face of the next adjacent blade and a sealed chamber between said piston and blocking blade will be created, said curved faces of said piston and blocking blade arranged to engage initially along a line toward the outer end of said blocking blade to cause rotation of said element with the line of engagement between said piston and blocking blade moving inwardly as rotation of said blocking blade continues, said gear tooth and gear tooth faces then coming into operative engagement to continue the rotation of said element through said 2. In a rotary steam engine having a plurality of curved cylinders in which the inner wall of each cylinder is cylindrical and comprises the outer discontinuous cylindrical surface of an interior stationary body, connected side and outer walls which rotate concentrically with respect to said inner wall, blocking means defining the ends of said cylinders, said blocking means comprising a plurality of four bladed rotatable ele ments mounted for rotation in the gaps in said discontinuous cylindrical wall, the surfaces of each blade being convex and having over the outer parts of the said surfaces the same curvature as the said discontinuous cylindrical inner wall, whereby the outer parts of the surfaces of opposite blades may be aligned with and comprise extensions of said discontinuous cylindrical inner wall, and whereby one of the blades extends radially outward to slidingly engage the rotating side and outer walls and act as the said blocking means, a plurality of pistons extending transversely of said cylinders and fixed to said rotating side and outer walls and adapted to slidingly engage said discontinuous cylindrical inner wall and the extensions thereof formed by the outer parts of the convex surfaces of said blades, the faces of said pistons having the outer parts of their surfaces concave and substantially cylindrical with a radius greater than the radius of the curvature of the outer parts of the faces of said blades, exhaust ports through the said outer rotating wall at positions in advance of each said piston, each said exhaust port located at a distance in advance of its related piston such that when said exhaust port has passed the other end of the blocking blade as the piston approaches said blocking blade toward the end of the pistons stroke, said piston will be passing over an adjacent blade surface that comprises an extension of said discontinuous cylindrical inner wall and the space in said cylinder between the advancing piston and said blocking blade will be sealed, the said outer part of the face of each said piston adapted to make rolling engagement with the cooperating cylindrical surface of the blade when the piston engages said blade, and the inner end of each said piston comprising a gear tooth adapted to engage with cooperating gear shapped walls inwardly of the cylindrical surfaces of adjacent blades.

3. The Construction set forth in claim 2, each said rotatable element mounted on a hollow shaft, means for supplying steam to said shaft, steam ports passing through the hub of said rotatable element into each of the root areas between each pair of adjacent blades, valve means for controlling the delivery of steam from said shaft to those ports only that are between the blocking blade and the adjacent blade whose surface will constitute the extension of the stationary discontinuous cylindrical inner wall at the beginning of the next cylinder, said steam being delivered by said valve means behind the piston after the piston has caused rotation of said blocking blade and has moved the blade which was formerly the blocking blade, into inner wall extension position in the next cylinder.

4. The construction set forth in claim 2, the opposed faces of said blocking blade and piston being so disposed that when said piston face initially engages said blocking blade face it will be along a transverse line of contact toward the outer end of said blocking blade and said line of contact will shift radially inward as rotation of said blocking blade continues under the influence of said piston.

5. The construction set forth in claim 2, the gaps in said stationary discontinuous cylindrical inner wall being in the form of substantially semi-cylindrical spaces each containing three of the said four blades of each element, a shaft for supporting each said rotatable element and extending beyond the ends of said element, a main engine mounting shaft extending axially through said body, circular face plates on opposite sides of said body to support the ends of said rotatable element shafts, said body and face plates fixed against rotation on said engine mounting shaft, and side plates integral with the walls of said curved cylinders covering said body and face plates and mounted for rotation on said main shaft.

6. The construction set forth in claim 2, each said rotatable element mounted on a tubular shaft, a tubular engine mounting shaft extending axially through said body, circular face plates on opposite sides of said body to support the ends of said rotatable element mounting shafts, said body and face plates fixed against rotation on said engine mounting shaft, a steam pipe within said engine mounting shaft, connecting steam passages through said body, connecting ports through both said face plates, connecting pipes extending along the out side of said face plates, said last named pipes connected to both ends of the tubular shafts carrying said rotatable elements, and means for delivering steam to each rotatable element at one position only between adjacent blades at the pressure end of a cylinder behind a piston that has just entered said cylinder.

Patent No. Dated February 11, 1975 lnventofls) Anthony Nardi It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In column 1, line 65 words "of each" are omitted between the words "wall" and "blade".

In column 4, line 33, "inner" should read "interior".

in Column 6, line 13 "aa'" should read "a'".

In Claim 2, line 39, "other" should read "outer".

Signed and sealed this 15th day of July 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks 

1. In a rotary steam engine having a stationary discontinuous cylindrical inner wall and rotating outer and side walls to form a curved cylinder, a piston attached to the rotating walls and a four bladed rotatable element associated with the inner wall, one of said blades extending across and blocking said cylinder, means for causing rotation of said rotatable element through 90* whereby said piston may pass thereby, said means comprising curved faces on the blades of said rotatable elements of the same radius as said inner walls, curved faces on said piston having a radius greater than the radius of said inner wall, the inner end of said piston comprising a gear tooth, cooperating gear tooth faces at the root areas between adjacent blades of said rotating element, and an exhaust port through said outer wall located in advance of its related piston a distance such that when said exhaust port has moved beyond said blocking blade, said piston will have started its travel over the curved face of the next adjacent blade and a sealed chamber between said piston and blocking blade will be created, said curved faces of said piston and blocking blade arranged to engage initially along a line toward the outer end of said blocking blade to cause rotation of said element with the line of engagement between said piston and blocking blade moving inwardly as rotation of said blocking blade continues, said gear tooth and gear tooth faces then coming into operative engagement to continue the rotation of said element through said 90*.
 2. In a rotary steam engine having a plurality of curved cylinders in which the inner wall of each cylinder is cylindrical and comprises the outer discontinuous cylindrical surface of an interior stationary body, connected side and outer walls which rotate concentrically with respect to said inner wall, blocking means defining the ends of said cylinders, said blocking means comprising a plurality of four bladed rotatable elements mounted for rotation in the gaps in said discontinuous cylindrical wall, the surfaces of each blade being convex and having over the outer parts of the said surfaces the same curvature as the said discontinuous cylindrical inner wall, whereby the outer parts of the surfaces of opposite blades may be aligned with and comprise extensions of said discontinuous cylindrical inner wall, and whereby one of the blades extends radially outward to slidingly engage the rotating side and outer walls and act as the said blocking means, a plurality of pistons extending transversely of said cylinders and fixed to said rotating side and outer walls and adapted to slidingly engage said discontinuous cylindrical inner wall and the extensions thereof formed by the outer parts of the convex surfaces of said blades, the faces of said pistons having the outer parts of their surfaces concave and substantially cylindrical with a radius greater than the radius of the curvature of the outer parts of the faces of said blades, exhaust ports through the said outer rotating wall at positions in advance of each said piston, each said exhaust port located at a distance in advance of its related piston such that when said exhaust port has passed the other end of the blocking blade as the piston approaches said blocking blade toward the end of the piston''s stroke, said piston will be passing over an adjacent blade surface that comprises an extension of said discontinuous cylindrical inner wall and the space in said cylinder between the advancing piston and said blocking blade will be sealed, the said outer part of the face of each said piston adapted to make rolling engagement with the cooperating cylindrical surface of the blade when the piston engages said blade, and the inner end of each said piston comprising a gear tooth adapted to engage with cooperating gear shapped walls inwardly of the cylindrical surfaces of adjacent blades.
 3. The Construction set forth in claim 2, each said rotatable element mounted on a hollow shaft, means for supplying steam to said shaft, steam ports passing through the hub of said rotatable element into each of the root areas between each pair of adjacent blades, valve means for controlling the delivery of steam from said shaft to those ports only that are between the blocking blade and the adjacent blade whose surface will constitute the extension of the stationary discontinuous cylindrical inner wall at the beginning of the next cylinder, said steam being delivered by said valve means behind the piston after the piston has caused rotation of said blocking blade and has moved the blade which was formerly the blocking blade, into inner wall extension position in the next cylinder.
 4. The constrUction set forth in claim 2, the opposed faces of said blocking blade and piston being so disposed that when said piston face initially engages said blocking blade face it will be along a transverse line of contact toward the outer end of said blocking blade and said line of contact will shift radially inward as rotation of said blocking blade continues under the influence of said piston.
 5. The construction set forth in claim 2, the gaps in said stationary discontinuous cylindrical inner wall being in the form of substantially semi-cylindrical spaces each containing three of the said four blades of each element, a shaft for supporting each said rotatable element and extending beyond the ends of said element, a main engine mounting shaft extending axially through said body, circular face plates on opposite sides of said body to support the ends of said rotatable element shafts, said body and face plates fixed against rotation on said engine mounting shaft, and side plates integral with the walls of said curved cylinders covering said body and face plates and mounted for rotation on said main shaft.
 6. The construction set forth in claim 2, each said rotatable element mounted on a tubular shaft, a tubular engine mounting shaft extending axially through said body, circular face plates on opposite sides of said body to support the ends of said rotatable element mounting shafts, said body and face plates fixed against rotation on said engine mounting shaft, a steam pipe within said engine mounting shaft, connecting steam passages through said body, connecting ports through both said face plates, connecting pipes extending along the outside of said face plates, said last named pipes connected to both ends of the tubular shafts carrying said rotatable elements, and means for delivering steam to each rotatable element at one position only between adjacent blades at the pressure end of a cylinder behind a piston that has just entered said cylinder. 